Potassium (K) is an essential element in plants and is considered one of the three macronutrients, along with nitrogen and phosphorus. Its relative amount is analyzed and reported in almost all routine soil samples. Therefore, it's obvious that it is important.
Unfortunately, with recent price increases, it has gone from being the least expensive to the most expensive of the three macronutrients. In this article, I'll look at where potassium deficiencies are most likely to occur, the consequences of these deficiencies and management strategies to address these situations.
Plants take up potassium in the ionic form (K+). Since soils have a net negative electrical charge due to the clays and organic matter, the positively charged potassium is held magnetically to the clays and organic matter particles in the soil. The more clay and organic matter there is in the soil, the more strongly potassium is held. If there is little clay and/or organic matter in the soil, potassium can leach out of the root zone in heavy rains.
To read the entire article, link here.